Rookie long snapper Nick Guess said he got the call from the Raiders on Wednesday about 3 p.m. in his hometown of Knoxville, Tenn.

Three hours later he was on a flight to Oakland, which touched down late that night. And at 7 a.m. Thursday, he was on the field at team headquarters along with five other free agent long snappers.

“They took us out, we went through a tryout, and they took three of us over to get physicals,” Guess said. “And when we came back, they chose me.”

Guess (6-foot-2, 251 pounds), who played for the University of Tennessee, was signed to the practice squad as an insurance policy if veteran long snapper Jon Condo can’t play Sunday at Miami.

Condo suffered a concussion Monday night against San Diego in the second quarter while covering a punt and didn’t return to the game. He has yet to be cleared by doctors to practice.

After Condo left the game, backup long snapper Travis Goethel, who hadn’t long-snapped in a game since high school, had a nightmare. He had two bad punt snaps. On his one good punt snap, Chargers' TE Dante Rosario raced free up the middle to block Shane Lechler’s punt.

Raiders' coach Dennis Allen said Guess would be promoted to the 53-man roster if Condo isn’t able to play.

“He’s involved in the (concussion) process right now,” Allen said of Condo. “That’s going to go all the way up until Saturday before we know for sure. Or at least there’s the potential that it could go to Saturday before we know.”

Condo was briefly in the Raiders’ locker room after practice but declined to comment.

Guess, who was in the Chargers’ training camp before being waived Aug. 27, has been long-snapping for more than a decade. He said his father, a football coach, had been a long snapper in high school and taught him the skill.

Practice squad shuffle: The Raiders signed CB Coye Francies and DL Brandon Bair to the practice squad. Francies was waived from the 53-man roster earlier this month. Bair, who played at Oregon, spent time with Kansas City last season but was waived Aug. 31

The Raiders waived LB Nathan Stupar, a seventh-round draft pick from Penn State, WR Brandon Carswell and DT Vaughn Meatoaga from the practice squad.

Injury report: LB Rolando McClain (ankle) and RB Taiwan Jones (ribs) missed practice and are day-to-day, Allen said. Both were injured against San Diego. Condo, CB Ron Bartell (fractured shoulder blade) and WR Jacoby Ford (foot surgery) were also out. C Alex Parsons was limited in practice with a shoulder injury. WR Juron Criner (ankle), Denarius Moore (hamstring) and DT Richard Seymour (knee) were also limited.

Follow Raiders reporter Eric Gilmore on Twitter: @CBSRaiders.